In general, a refrigerator includes cooling cycle components such as a compressor, a condenser, an expansion valve, an evaporator, and the like. By using the cooling cycle components, cold air is generated to preserve food items in a fresh state for an extended period of time.
Such a refrigerator is structured in a manner that the inside of its main body which defines an outer appearance thereof, is partitioned into a refrigerator compartment and a freezer compartment to preserve food items in one of the compartments for refrigeration and freezing, respectively, depending on their preservation temperature.
Meanwhile, a modern refrigerator has a three-door structure such that, in addition to the traditional two storage spaces composed of a refrigerator compartment and a freezer compartment for preserving food items at predetermined fixed temperatures, there is provided with a temperature controlled compartment which is a separate storage space for preserving therein food items that need to be preserved at different temperatures from each other.
FIG. 1 illustrates a refrigerator having a conventional temperature controlled compartment.
As shown in FIG. 1, a refrigerator 10 includes a freezer compartment 20, a refrigerator compartment 30, and a temperature controlled compartment 40 which is a separate storage space disposed under the refrigerator compartment 30, wherein the freezer compartment 20, the refrigerator compartment 30, and the temperature controlled compartment 40 are partitioned by a partition wall 11.
The conventional refrigerator 10 is operated in such a way that the cold air supplied from an evaporator (not shown) built in a rear duct of the refrigerator 10 is blown into the freezer compartment 20 through a freezer compartment fan (not shown), and a part of the cold air supplied to the freezer compartment 20 is introduced to the refrigerator compartment 30. In the meantime, a part of the cold air cooling down the refrigerator compartment 30 through a refrigerator compartment fan (not shown) is introduced to the temperature controlled compartment 40 via a cold air inlet (not shown) which is formed at the lower portion of the refrigerator compartment 30.
However, in the conventional refrigerator where inside temperature thereof is cooled by the operation of an evaporator, the refrigerator is poor in cooling efficiency because the entire cooling cycle is required to be run to cool down the temperature controlled compartment 40 if the outside air is flowed into the inside of the temperature controlled compartment 40 while its door is open for use.
It is also difficult to maintain the temperature of the temperature controlled compartment 40 accurately at a specific value simply by regulating an amount of cold air supplied from the freezer compartment 20 or from the refrigerator compartment 30.
Moreover, there is another difficulty in temperature controlled between refrigeration and freezing, depending on the temperature controlled compartment's usage conditions set by a user.
In addition, although not shown in FIG. 1, if the freezer compartment 20, the refrigerator compartment 30 and the temperature controlled compartment 40 are cooled individually by their own cooling units such as evaporators or blower fans embedded in a rear side of the refrigerator, since the cooling units occupy too much space of the refrigerator, the space efficiency of the temperature controlled compartment 40 is reduced. As for the manufacturing process, if a cooling unit is assembled onto the rear side of the relatively small temperature controlled compartment 40, an assembly process becomes difficult and the number of assembly processes is increased, which gives rise to a number of inefficiencies such as an increase of complexity in manufacturing procedure of refrigerator, an increase of material and labor costs, and the like.